1. Field of the Invention
This invention relates to rolling mill bearing chock supports and more particularly to an improved wearplate structure providing increased support and alignment stability for the work roll bearing chocks in a rolling mill.
2. Description of the Prior Art
The invention may readily be adapted for use in various rolling mill configurations, but is particularly well-suited for application to a four high strip mill and will be described in conjunction with such a mill. More specifically, the invention will be described with particular reference to a high-speed four high strip mill of the general type disclosed and described in U.S. Pat. No. 3,733,875. Mills of this type employ upper and lower work rolls which cooperate to define a pass line at their nip for the strip to be rolled therebetween, with the ends of the rolls being supported in bearing chocks which, in turn, are mounted in the windows of mill housings disposed one on each side of the pass line, with the chocks and the work rolls supported therein being removable as a unit from the operator side of the mill. Upper and lower backup rolls also have their ends supported in chocks mounted in the mill housings, with power-driven screwdowns forcing the backup rolls into rolling engagement with the work rolls during operation of the mill.
The axes of the upper and lower work rolls and the large upper and lower backup rolls are contained in a common vertical plane so that the extremely heavy workloads exerted by the power-driven screwdowns, through the backup roll chocks and rolls, to the work rolls should theoretically produce only a vertical load on the work bearing chocks in the static load condition. However, minor misalignments inherent in such equipment as a result of manufacturing tolerances, wear, strain, and the like, and as a result of loads produced by the roll drive and by the workpiece moving through the millstand, produce very heavy loads on the work roll chocks tending to upset the coplanar relation of the roll axes and, as a result, the millstand housings must place heavy restraining loads on the work roll chocks. These heavy loads have, in the past, caused wear on the bearing surfaces of both work roll chocks and the mill housing. To minimize this wear, and to facilitate maintenance of the roll stands, it has been conventional practice to provide wear plates, or liners, in the form of high-strength hardened steel plates on the face of the mill housing and on the adjacent face of the roll chocks. While these liner plates have generally been effective in reducing wear and keeping the chocks centered in the mill housing, there have been instances where the chocks have been permitted to move sufficiently to produce a hammering effect causing excessive wear on the liner plates and in extreme cases to cause wear or damage to the face of the mill housing beneath the liner. This has been particularly true in the case of the lower work roll chock which generally has been provided with substantially smaller liner plate area than the top work roll chock. Examples of known rolling mills wherein liner plate for the bottom work roll chock is substantially smaller than that of the top work roll chock can be found in the above-mentioned U.S. Pat. No. 3,733,875 and U.S. Pat. No. 3,864,954. Other known rolling mill configurations similarly employ liner plates of unequal area on the lower and upper work roll bearing chocks.
It is a primary object of the present invention to provide an improved chock structure for the work rolls of a rolling mill.
Another object of the invention is to provide a lower work roll bearing chock having an increased liner support surface.
Another object of the invention is to provide a rolling mill including upper and lower work roll bearing chocks having liner plates rigidly mounted thereon and including means for providing an increased vertical dimension for the lower work roll bearing chock liner plate to thereby provide greater strength and dimensional stability for the lower work roll bearing chock.
Another object is to provide a rolling mill in which the upper and lower work roll chocks have substantially equal bearing face areas in contact with the supporting mill housing.